Diazotype material



United States Patent 3,311,475 DIAZOTYPE MATERIAL Arie van Loon and Bernardus Hubertus Huibers, Veulo, Netherlands, assignors to Chemische Fabriek L. van der Grinten N.V., Venlo, Netherlands, a corporation of Dutch law No Drawing. Filed July 14, 1964, Ser. No. 382,637 Claims priority, application Netherlands, July 19, 1963,

Claims. c1. 9691) This invention relates to a new class of diazonium compounds and to diazotype materials and diazotype processes which make use of such compounds. This diazotype material may, for instance be so-called one-component diazotype material wherein the material contains the diazonium compound and is developed with a liquid developer containing an azo coupling component, or so-called two com ponent diazotype material wherein the material contains both the diazonium compound and the azo coupling component and is developed with the aid of ammonia vapour, or diazotype material which is developed by heat treatment.

In Fiat Final Report 813, pages 137 and 138, and Dutch patent specification No. 51,536 (corresponding to US. Patent No. 2,286,701), several 4-diazo-2,5-dialkoxyphenylthioalkyl, -cycloa1kyl, -aralkyl, and -aryl ethers for the sensitizing of diazotype materials are described. However, only the 4-diazo-2,5dialkoxyphenylthioarybethers, particularly the 4-diazo-2,5-dimethoxyand diethoxyphenylthio (o and p) tolyl ethers, have proved to be of practical value (compare British patent specification No. 759,045 and German patent specification No. 896,591).

One-component diazotype material sensitized with such compounds furnishes copies showing fine black azo-dyestutf images upon imagewise exposure and development according to the so-called thin-layer method by means 0t bufiered weakly acid phloroglucinol developers, which are very attractive because of their high keeping quality. (In the thin-layer method a very thin layer of a developing solution is applied to the exposed diazotype material.) However, the azo-dyestuffs thus obtained have only low absorption for radiation in the near ultra-violet part of the spectrum, the radiation with the aid of which copies are made in the diazo-type process. In consequence, copies on translucent diazotype materials, sensitized with such diazo compounds, are not very suitable, if at all, for use as so-called intermediate copies from which further copies are made.

Judged by modern standards, diazotype materials sensitized with the 4-diazo-2,5-dialkoxyphenylthiotolyl ethers have moderate light-sensitivity. Moreover, using weakly acid phloroglucinol developers such one-component diazotype material often develops too slowly, particularly when the copy is not heated after the application of the developing liquid.

According to a first feature of the present invention .there are provided diazonium compounds of the general formula:

NzX

in which X represents an anion, R represents an alkyl, branched alkyl, cycloalkyl or aralkyl radical, COR represents an acyl radical, R being hydrogen or an organic radical, R represents a saturated or unsaturated organic ice radical or a cyano group, and R represents an alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl radical.

The foregoing diazonium compounds in diazotype material have the advantages that they develop much more rapidly than diazotype material sensitized with the corresponding 2,5-dialkoxy compounds and, when polyvalent phenols such as resorcinol or phloroglucinol are used as azo-coupling components, often yield copies in azo-dyestufis having better absorption for ultra-violet radiation.

In the above definition by acyl is to be understood the radical COR in which R is hydrogen or an organic radical. Such an interpretation of acyl is usual in diazotype literature. (Compare British patent specifications Nos. 615,774, 347,430 and 539,031.)

The saturated or un-saturated organic radicals R according to the above definition include saturated and unsaturated aliphatic and cycloaliphatic radicals, aromatic radicals, acyl radicals, and the cyano group.

The diazotype material according to the invention is preferably one-component diazotype material. Upon development with weakly acid phloroglucinol developers it yields copies with brown to black azo-dyestulf images and upon development with weakly alkaline phloroglucinol developers it yields copies with somewhat lighter brown azo-dyestuff images.

In a particular embodiment of the invention one-component diazotype material which is suitable for use as a light-sensitive planographic printing plate is employed on which by imagewise exposure and development with a liquid containing an azo coupling component a hydrophobic ink-receptive image is formed.

The diazotype material according to the invention may, however, also be two-component diazotype material. in such material a slowly coupling azo-component, such as 2-hydroxy-8-biguanidinonaphthalene, Z-hydroxynaphtha lene-3,6-disulphonic acid or 7'-hydroxy-1',2',4,5-naphthimidazole is preferably used.

The diazotype material according to the invention may also be heat-developable diazotype material, e.g. material such as described in British patent specification No. 815,005 or United States Patent No. 3,284,201.

The diazotype material according to the invention may have an opaque support, such as white paper or opaque linen, or a transparent support, such as tracing paper, tracing linen, cellulose-ester foil, polyester foil, transparentized paper and the like. The diazonium compound may be applied direct on the surface of the supportor may be present in a hydrophilic film layer which may or may not be attached to the support by means of one or more sub-layers.

The following table lists, but is not a complete list of, diazonium compounds which can be used in the diazotype material according to the invention:

TABLE (4-diazo-5-N-acetyl-N-methylamino-2-methoxy) phenylthioethyl ether,

(4-diazo-5-N-acetyl-N-methylamino-Z-n-butoxy) phenylthioethyl ether,

(4-diazo-5-N-acetyl-N-methylamino-Z-cyclopentoxy) phenylthioethyl ether,

(4-diazo-5-N-benzoyl-N-methylamino-2-butoxy)phenylthioethyl ether,

(4-diazo-5 -N-acetyl-N-ethylamino-2-methoxy phenylthiobenzyl ether,

( 4-diazo-5-N-butyryl-N-ethylamino-2-methoxy) phenylthiobenzyl ether,

(4-diazo-5-N-acetyl-N-methylamino-2-(4-chloro)phenoxy) phenylthio-(4'-methyl) phenyl ether,

Oxalic bis-(N-methyl) (N-2-diazo-4-methoxy-5'-(4'- methyl) phenylthiophenyl) amide,

I 3 TABLE-Continued (4-diazo-5-N-ethoxycarbonyl-N-methylamino-Z-methoxy) phenylthioethyl ether, (4-diazo-5-N-ethoxycarbonyl-N-methylamino-Z-n-butoxy) phenylthioethyl ether, (4-diazo-5-N-ethoxycarbonyl-N-methylamino-Z-methoxy) phenylthiocarboxymethyl ether, 4-diazo-5-N-ethoxycarbonyl-N-methylamino-2-rnethoxy) phenylthiopotassium sulphomethyl ether, (4-diazo-5-N-ethoxycarbonyl-N-methylamin0-2-methoxy) phenylthio-2'-hydroxyethyl ether, (4-diazo-5-N-eth0xycarbonyl-N-methylamino-2-methoxy) phenylthio-2-methyl-4',4'-dimethylpentyl ether, (4-diazo-S-N-ethoxycarbonyl-N-methylamino-2-methoxy) phenylthioallyl ether, (4-diazo-5-N-ethoxycarbony1-N-methylamino-Z-methoxy) phenylthiobenzyl ether, (4-diazo-5-N-ethoxycarbonyl-N-methylamino-Z-methoxy) phenylthio-(4'-methyl)phenyl ether, (4-diazo-S-N-isobutoxycarbonyl-N-methylamino-2-methoxy) phenylthioethyl ether, (4-diazo-S-N-benzyloxycarbonyl-N-methylamino-Z-methoxy) phenylthioethyl ether, (4-diazo-5-N-phenoxycarbonyl-N-methylamino-2-methoxy) phenylthioethyl ether, (4-diazo-5-N-isobutoxycarbonyl-N-methylamino-2-methoxy) phenylthio-( 4-methyl phenyl ether, (4-diazo-5-N-benzyloxycarbonyl-N-methylamino-2-methoxy)phenylthio-(4-methyl) phenyl ether, (4-diazo-5-N-phenoxycarbonyl-N-methylarnino-2-methoxy phenylthio- (4-methyl phenyl ether, Adipic bis-(N-methyl) (N-2'-diazo-4-methoxy-5-ethylthiophenyl) amide, 4- ethoxycarbonylthio-5-methoxy-Z-N-ethoxycarbonyl-N- n-butylaminodiazobenzene, 4-cyanothio-5-methoxy-2-N-ethoxycarbonyl-N-methylaminodiazobenzene, (4-diazo-2-methoxy-5-N-methyl-N-2'-chloroethoxycarbonylamino) phenylthioethyl ether, (4-diazo-Z-methoxy-S-N-methyl-N-2'-diethylaminoethoxycarbonylamino) phenylthioethyl ether, (4-diazo-2-methoxy-5-N-2-hydroxyethyl-N-benzy1oxycarbonylamino phenylthioethyl ether, (4-diazo-2-benzyloxy-5-N-methyl-N-ethoxycarbonylamino)phenylthioethyl ether, (4-diazo-2-methoxy-S-N-methyl-N-ethoxycarb onylamino phenylthio propargyl ether. (4-diazo-2-methoxy-5-N-isopropyl-N-ethoxycarbonylamino)phenylthio-p-tolyl ether, (4-diazo-2-methoxy-5-N-cyclohexyl-N-ethoxycarbonylamino)phenylthio-p-tolyl ether, (4-diazo-2-methoxy-S-N-benzyl-N-acetylamino)phenylthio-p-tolyl ether, (4-diazo-2-methoxy-5-N-rnethyl-N-ethoxycarbonylamino) phenylthionaphthyl ether, (4-diazo-2-methoxy-5-N-methyl-N-ethoxycarbonylamino) phenylthio-horno-naphthyl ether.

These diazonium compounds are (preferably) applied in the form of their diazonium salts, such as diazonium chlorides, sulphates, nitrates, and metal chloride double salts (e.g., diazonium chlorostannates, chlorozincates), diazonium borofluorides, and the like.

They can be applied separately in the diazotype material according to the invention or be mixed together. Naturally they can also be used in admixture with diazonium compounds of other types. However, according as such mixtures have a lower content of diazonium compound according to the foregoing formula, the diazotype material according to the invention prepared with these mixtures will present the advantages described to a smaller degree.

The diazonium compounds of the foregoing formula with an etherified mercapto group in p-position and those with an acylthio group in p-position can be prepared by starting from S-chloro-Z-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxy-1-nitrobenzene.

5-chloro-2-(all yl, branched alkyl, cycloalkyl, or aralkyl)oxy-l-nitrobenzene is obtained from p-chlorophenol by nitrating this product and then etherifying the hydroxyl group.

S-chloro-Z-aryloxy-l-nitrobenzene is prepared from 2,5-dichloronitrobenzene, for which purpose this product is fused With a hydroxyaryl compound (phenol, naphthol) and potassium hydroxide.

5-chloro-2-(alkyl, branched alkyl, cycloalkyl, arallryl, or aryl)oxy-l-nitrobenzene is reduced to 5-chloro-2- (alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxyaniline, the amino group of which is then acylated. The product obtained is nitrated and then de-acylated. In the 5-chloro-4-nitro-2-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxyaniline thus formed the chlorine atom is replaced by a mono(alkyl, branched alkyl, cycloalkyl, or aralkyl)amino group, and then the free amino group by a chlorine atom (according to Sandmeyer).

In order to obtain the diazoniurn compounds with an etherified mercapto group in p-position, the S-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxy-4-chloro- Z-(alkyl, branched alkyl, cycloalkyl, or aralkyl)amino-lnitrobenzene thus formed, is converted with a mercaptan into S-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl) oxy-4-(substituent)thio-Z-(alkyl, branched alkyl, cycloalkyl or aralkyl)amino-l-nitrobenzene, which product is acylated, e.g., with a carbochloride or an ester of chloroformic acid, and reduced to S-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxy-4-(substituent)thio-Z-N- acyl-N-(alkyl, branched alkyl, cycloalkyl, or aralkyl) aminoaniline, from which the diazonium compound is produced in the usual Way.

In order to obtain the diazonium compounds with an acylthio-4-group, S-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oXy-4-chloro-2-(alkyl, branched alkyl, cycloalkyl, or aralkyl)amino-l-nitrobenzene is brought into reaction with Na s and a carbochloride or an ester of chloroformic acid. The 4-acylthio-5-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl) oxy-2-N-acyl-N-(alkyl, branched alkyl, cycloalkyl, or aralkyl)amino-1-nitrobenzene thus obtained is reduced to the corresponding amino compound, which is subsequently diazotized.

The diazonium compounds with a cyanothio-4-group are prepared from 4-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxyaniline by successively acylating, nitrating, and de-acylating this product. 4- (alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxy-2-nitroaniline is converted according to Sandmeyer into the corresponding chloro-l-compound, the chlorine atom of which is subsequently replaced by an (alkyl, branched alkyl, cycloalkyl, or aralkyl)amino group. This amino group is then acylated.

Z-N-acyl-N-(alkyl, branched alkyl, cycloalkyl, or aralkyl)arnino-5-(alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)oxy-l-nitrobenzene is provided in the 4-position with a cyanothio group by bringing this product into reaction with Br and KCNS.

From the reaction product the diazonium compound is produced by reduction and diazotization.

In general, the diazonium compounds with an (alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl)thio substituent in the 4-position are preferred. They are readily accessible by preparation in the manner described above in respect of compounds having an etherified mercapto group in p-position. They usually couple to yield a preferred rather dark brown azo-dyestuff image.

Hence, a preferred diazotype material according to the invention contains a diazonium compound according to the above general formula, in which the substituent R represents an alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl radical.

Other preferred compounds are the diazonium compounds according to the above general formula in which R represents a non-branched alkyl group with at most 5 carbon atoms, preferably with fewer than 3 carbon atoms. Diazotype material sensitized with these diazonium compounds has not only higher coupling activity, but also considerably greater light-sensitivity than diazotype material which has been sensitized with a corresponding 2,5-di-alkoxy compound. (This appears, for instance, upon exposure in a photoprinting apparatus which is equipped with a high-pressure mercury vapour lamp. This diazotype material according to the invention often proves to be over one and a half times more light-sensitive than corresponding diazotype material which has been sensitized with the corresponding 2,5- di-alkoxy compound.)

Among the diazonium compounds according to the above general formula, those in which R represents an alkoxy, benzyloxy, or phenoxy radical are outstanding because they are more stable than the corresponding diazonium compounds in which R represents an alkyl, benzyl, or phenyl radical and moreover the azo-dyestuff images formed from them are darker and have better water-fastness, so that with those diazonium compounds it is possible to make a diazotype material yielding copies with a dark, often almost black, azo-dyestuif image, which, notwithstanding the dark shade, has good absorption for ultra-violet radiation and shows no bleeding of the azo-dyestuff upon development.

Very attractive compounds are the diazonium compounds according to the above general formula in which R represents an alkyl, branched alkyl, cycloalkyl, aralkyl, or aryl radical and R; a methyl group.

By starting from the corresponding 4-nitro-2,5-dimethoxyphenylthio ether, these diazonium compounds can be prepared in a simple way and in good yields by heating the ether in an autoclave with a primary nonaromatic amine, upon which the methoxy group ortho with respect to the nitro group is replaced by a monosubstituted amino group, subsequently the amino group thus introduced is acylated, and the resulting nitro compound is then converted into a diazonium compound in the usual way.

Moreover, the diazonium compounds according to the above definition can be applied better than the corresponding diazonium compounds in which R represents a higher alkyl group in aqueous sensitizing liquids, together with aromatic sulphonic acids such as the wellknown stabilizer naphthalene-1,3,6-t-risulphonic acid, without precipitates being formed in those liquids.

In Fiat Final Report 813, pages 86, 87, and 1095 benzene diazo compounds with a N-acetyl-N-methylamino group in ortho position are described. Furthermore they may also carry methyl or methoxy substituents. These diazo compounds have low light-sensitivity and couple very actively, whilst forming very light-coloured yellow to red azo-dyestuffs of low contrast. With these diazo compounds no diazotype material that is suitable in practice can be made.

In the diazotype material according to the invention the auxiliary agents commonly used (in the diazotype materials) can be applied, e.g. acids, such as citric acid, tartaric acid, and boric acid; stabilizers, such as benzene and naphthalene sulphonic acids, p-phenol sulphonic acid, and their water soluble salts; metal salts, such as zinc chloride, magnesium chloride, nickel sulphate, and alum; substances serving to increase the developing speed, such as glycerol, polyethylene glycol, and urea; surface improving substances, such as finely divided silica (colloidal or non-colloidal), aluminum oxide, barium sulphate, rice starch, etc.; binders, such as gelatin, gum arabic, cellulose ethers, starch derivatives, polyvinyl alcohol; dispersions of synthetic resins, such as dispersions of cationic, non-ionic, and anionic polyvinyl acetate; substances serving to improve the background of the copies, such as thiourea.

The phloroglucinol developers which are used in the 6 one-component diazotype process often vary as to their composition and acidity. Three weakly acid phlorogluci nol developers and one weakly alkaline phloroglucinol developer are described below. These are practical formulations and are used for development in the examples following hereafter: (the words Sorbit and Tergitol being Registered Trademarks).

Developer A is a solution of:

4 g. of phloroglucinol 0.1 g. of acetoacetanilide 3 ml. of Z-ethyl l-hexanol sulphate Tergitol 08 (from Union Carbide & Carbon Corp., New York ,17, USA.)

g. of beet sugar 2.5 g. of benzoic acid 14 g. of sodium benzoate 135 g. of sodium formate in 1000 ml. of water.

The pH of this liquid is approximately 5.8. Developer B is a solution of:

The pH of this liquid is 6.5. Developer C is a solution of:

5 g. of phloroglucinol 1 g. of resorcinol 3 g. of dipotassium phosphate 3 ml. of Tergitol 08 52 g. of maleic anhydride 75 ml. of potassium hydroxide solution (13.5 N) in 1000 ml. of Water.

The pH of this liquid is 6.9.

Developer D is a solution of:

g. of thiourea 5.4 g. of phloroglucinol 6.5 g. of resorcinol 1 g. of the potassium salt of hydroquinone-monosulphonic acid 5 g. of sorbitol 15 -g. of beet sugar g. of potassium tetraborate (5 aq.)

1.5 g. of isopropyl naphthalene sulphonic acid in 1000 ml. of water.

The pH of this liquid is approximately 9.5.

The following examples will serve to illustrate the invention. In these examples the following names used are registered trademarks: Vinnapas, Nalcamine, Rotafix.

Example I A sheet of white base paper of Weight 80 g./m. suitable for the diazotype process is sensitized with a solution of:

17.5 g. of 4 benzylthio 5-methoxy-2-N-butyryl-N-ethylaminobenzene diazonium chloride, zinc chloride double salt 4 g. of tartaric acid 1.5 g. of boric acid 2.5 g. of gelatin 30 ml. of the polyvinylacetate dispersion Vinnapas H. (from Wacker Chemie G.m.b.H., Munich, Germany) 1000 ml. of water and dried.

A sheet of light-sensitive material thus obtained is referred to hereinafter as Sheet 1.

Another sheet of base paper of the same kind is sensitized with a similar solution to that mentioned above, in which, however, an equivalent quantity of 4-benzylthi0- 2,5dimethoxybenzene diazonium chloride, zinc chloride double salt, is used instead of 17.5 g. of 4-benzylthio-5- methoxy 2 N butyryl-N-ethylaminobenzene diazonium salt.

The sheet thus prepared is referred to hereinafter as Sheet II.

In an exposure apparatus for the diazotype process, Sheet I is exposed underneath a transparent ink drawing until all the diazonium compound underneath the image-free portions of the drawing has just bleached out. Then Sheet II is exposed underneath the same drawing in the same apparatus during an equal period of time.

Both sheets are developed with the developer A described above, according to the so-called thin-layer method. Although both diazonium compounds have high coupling activity, it is clearly observable that the image on Sheet I has been developed more rapidly than that on Sheet II.

The copy obtained with Sheet I shows a brown image on a clear white background. The copy obtained with Sheet II shows a black image on a foggy grey background.

The diazonium compound used in Sheet I is prepared as follows:

-chloro-2-methoxyaniline is acetylated, nitrated, and deacetylated. The 5 chloro 4-nitro-2-methoxyaniline is converted into 5-ethylamino-4-nitro-2-rnethoxyaniline with mono-ethylarnine.

This product is diazotized and then sandmeyered to 5- ethylamino-4-nitro-2methoxy 1 chlorobenzene, from which through reaction with benzylmercaptan the S-ethylamino-4-nitro-2-methoxyphenylbenzylthio ether, melting at 95-97 C., is obtained. This product is converted with butyryl chloride into the S-N-ethyl-N-butyrylarnino-4-nitro-Z-methoxyphenyl-benzylthio ether. The nitro group is catalytically reduced and the amino group thus formed is diazotized, after which the diazonium compound is obtained in the form of the chlorozincate.

Example II White base paper of weight 50 g./m. suitable for the diazotype process, which has been transparentized with an alcoholic resin solution, is sensitized with a liquid containing:

50 g. of adipic bis (N-methyl) (N-2'-diazo-4-methoxy-5'- ethylthiophenyl)amide chlorozincate 5 g. of tartaric acid 1 g. of boric acid 2.5 g. of gum arabic ml. of Vinnapas H. 60

1000 ml. of water and dried.

A sheet of the very light-sensitive diazotype paper thus prepared is exposed underneath a letter which has been typed on one side until the diazonium compound underneath the white image portions of the letter has largely bleached out, and is then developed with developer C according to the so-called thin-layer method.

The copy thus obtainedshows a brown image on a foggy light-brown background and is eminently suitable for use as an intermediate original for making further copies.

The diazonium compound used in this example is prepared as follows:

5-chloro-2-methoxyaniline is acetylated and nitrated. The 5-chloro-4-nitro-2-methoxy-N-acetylaniline is brought into reaction with monomethylamine after de-acetylation. In the 5 rnethylamino 4 nitro 2 methoxyaniline thus formed the free amino group is subsequently replaced by a chlorine atom through sandmeyering. By causing the 5-rnethylamino-4-nitro-2-methoxy l chlorobenzene thus formed to react with ethylmercaptan, 4-ethylthio-2- methylamino-S-methoxy-l-nitrobenzene is obtained, which is acylated with adipyl chloride to adipic bis (N-methyl) (N 2' nitro 4 methoxy 5 ethylthiophenyl)amide. This product melts at 190-192 C. Its nitro groups are catalytically reduced, after which from the diamino compound the bis-diazonium chlorozincate is obtained in the usual way.

Example III Natural tracing paper of weight g./m. is sensitized with the following solution:

365 g. of 4-(4'-methylphenyl)thio-5-methoXy-2-N-acetyl- N-methylaminobenzene diazonium chloride, zinc chloride double salt 6 g. of citric acid 30 g. of the potassium salt of benzene-1,3-disulphonic acid 250 ml. of'ethanol (96%) 750 ml. of water and dried.

A sheet of the diazotype paper thus obtained is exposed underneath an ink drawing until the diazo compound underneath the image-free portions of the drawing has largely bleached out. It is then developed with developer B.

The copy shows a brown image on a foggy light-brown background.

If 4-(4'-methylphenyl)thio-2,5-dimethoxybenzene diazonium chloride, zinc chloride double salt, had been used in the above-mentioned liquid, the diazotype paper thus obtained would have been less light-sensitive, would have had a lower developing speed, and would have given copies with a blue-black azo-dyestuff image having lower absorption for ultra-violet radiation.

The diazonium compound used in the above-mentioned sensitizing liquid is prepared as follows:

5-chloro-2-methoxyaniline is acetylated and then nitrated. After de-acetylation, the 5 chloro 4 nitro 2- methoxyaniline is converted with monomethylamine into 5-methylamino-4-nitro-2-rnethoxyaniline, in which product the free amino group is replaced by a chlorine atom through sandmeyering. By causing the 5-methoxy-4- chloro-2methylamino-l-nitrobenzene thus formed to react with p-tolylmercaptan and then acetylating the Z-methylamino group, 5 methoxy 4 p-tolylthio-Z-N-methyl-N- acetylamino-l-nitrobenzene, melting at l54-l55 C., is obtained. This nitro compound is catalytically reduced to the corresponding amine, which is then diazotized. The resulting diazonium compound is obtained in the form of the zinc chloride double salt.

Example IV A cellulose acetate layer of weight about 20 g./m. applied on natural tracing paper of weight about 80 g./m. is superficially hydrolysed to a depth of about 4 microns and, after removal of the chemicals used for the hydrolysis by washing with water, is sensitized with the following solution:

49.5 g. of 4-ethylthio-S-n-butoXy-IZ-Jacetyl-N-methylaminobenzene diazonium chloride zinc chloride double salt 6 g. of tartaric acid 1 g. of gum arabic 250 ml. of ethanol (96%) 750 ml. of water and dried.

A sheet of the diazotype paper thus obtained is exposed underneath a line drawing until all the diazonium compound underneath the image-free portions of the drawing has bleached out. It is then developed with developer B.

The copy shows a violet-brown azo-dyestutf image having good absorption for ultra-vi0let radiation.

If the above-mentioned liquid had contained instead of the S-butoxy-Z-N-acetyl-N-methylamino diazonium compound, an equivalent quantity of 4-ethylthio-2,5-di-nbutoxybenzene diazonium chloride, zinc chloride double salt, the diazotype paper thus obtained would have been less light-sensitive, would have had a lower developing speed, and would have given copies with dark-blue azodyestuff images having lower absorption for ultra-violet radiation.

The diazonium compound used in this example can be prepared as follows:

p-Chlorophenol is nitrated, and the 4-chloro-2-nitrophenol thus obtained is butylated with n-butyl bromide to 4-chloro-2-nitrophenyl-n-butyl ether. The nitro group of this product is reduced and the amino group thus formed is acetylated with acetic anhydride. The 4-chloro-2- acetylaminophenyl-n-butyl ether is nitrated, de-acetylated, and then brought into reaction with monomethylamine. S-nitro-4-methylamino-2-aminophenyl-n-butyl ether is obtained. The amino group of this product is replaced by a chlorine atom through diazotization and sandmeyering, after which the product thus formed is converted into 4- ethylthio--n-butoxy-2-methylamino-1-nitrobenzene with ethylmercaptan. This substance is brought into reaction with acetyl chloride, as a result of which 4-ethylt'hio-5- butoxy Z-N-methyl-N-acetylamino-l-nitrobenzene, melting at 110 C., is obtained.

The nitro group of this compound is catalytically reduced and the amino group thus formed is diazotized.

The diazonium compound is obtained in the form of the chlorozincate. 1

Example V Opaque linen of weight 150 g./m. suitable for the diazotype process is sensitized with a solution of:

40 g. of 4-ethylthio-S-methoxy-Z-N-benzyloxycarbonyl- N-methylaminobenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 2 g. of boric acid 300 ml. of ethanol (96%) 700 ml. of water and dried.

A sheet of the light-ensitive diazotype linen thus obtained is imagewise exposed as described in Example II and developed with developer A.

The copy shows a black image on a foggy grey background.

If, instead of the diazonium compound mentioned, an equivalent quantity of the corresponding 4-ethylthio-2,5- di-methoxybenzene diazonium salt had been used, a copy with a black image on a foggy grey background would also have been obtained. However, the light-sensitive material would have had considerably lower light-sensitivity and a lower developing speed.

The diazonium compound used according to this example is prepared as follows:

5-chloro-2-methoxyaniline is acetylated, nitrated, and deacetylated. The 5 chloro-4-nitro-2-rnethoxyaniline thus obtained is converted with monomethylamine into S-methylarnino-4-nitro-2-methoxyaniline, which is then diazotized and sandmeyered to the corresponding chloro compound, from which the 5-methylamino-4-nitro-2- methoxyphenylethylthio ether is prepared by converting it with ethylmercaptan. This product is converted with the benzyl ester of chloroformic acid into 4-ethylthio-5- methoxy 2 -N-benzyloxycarbonyl N methylamino-lnitrobenzene, melting at 9698 C. From this nitro compound the above-mentioned diazonium salt is obtained in the usual way.

Example VI Paper coated with a baryta layer, for instance a sheet of paper of the quality Dryphoto mat (from Papeteries Steinbach & Cie., Malmedy, Belgium), is sensitized with a solution of:

25 g. of 4-(4-methyl)phenylthio-5-met'hoxy-2-N-ethoxycarbonyl-N-methylaminobenzene diazonium chloride, zinc chloride double salt 500 ml. of ethanol (96% 500 ml. of water and dried.

A sheet of the light-sensitive diazotype material thus obtained is imagewise exposed as described in Example IV and then developed by rubbing the image side of the diazotype material with a liquid containing:

30 g. of phloroglucinol 20 ml. of sodium hydroxide solution (11.2 N) 980 ml. of water The copy shows a brown-red image on a clear white background.

The copy is then rubbed with a so-called fixing solution, e.g. the liquid Rotafix B (from Rotaprint A. G., Berlin, Germany), and then washed with water.

The copy is now suitable for use as a planographic printing plate, and at least 1000 good ofiset prints can be made with it.

The diazonium compound used in this example may be made as follows:

Chloronitrohydroquinone dimethyl ether is brought into reaction with p-tolylmerca-ptan and the 4-p-tolylthio- 2,5-dimethoxy-l-nitrobenzene thus formed is heated for 20 hours with monomethylamine in an autoclave at a pressure of about 5 atmospheres, as a result of which the methoxy group ortho with respect to the nitro group is replaced by a monomethylamino group, which is acylated with the ethyl ester of chloroformic acid. 4-(4- me1thyl)phenylthio 5 methoxy 2 N ethoxycarbonyl- N-methylamino-l-nitrobenzene, melting at 123-125 C., is thus obtained.

The nitro group of this product is catalytically reduced, after which the diazonium salt is obtained from the amine in the usual way.

Example VII White base paper of weight g./m. suitable for the diazotype process is sensitized with a liquid containing:

30 g. of 4-ethylthio-5-methoxy-2-N-benzyloxycarbonyl- N-ethylaminobenzene diazonium chloride, zinc chloride double salt 7 g. of 4-(4'-methyl)phenylthio-Z,S-diethoxybenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 30 ml. of Vinnapas H. 60

1000 ml. of Water and dried.

A sheet of the diazotype paper thus obtained is imagewise exposed underneath a pencil drawing until the diazonium compound underneath the imagefree portions of the drawing has largely bleached out, and is then developed with developer A.

The copy thus obtained shows a black image on a foggy grey background.

If in the above sensitizing liquid, instead of 4-ethylthio S-methoxy-2-N-benzyloxycarbonyl-N-methylaminobenzene diazonium chloride, zinc chloride double salt, an equivalent quantity of the corresponding 4-ethylthio2,5- dimethoxybenzene diazonium compound had been used, the diazotype paper thus obtained would have been considerably less light-sensitive, would have had a lower developing speed, and would have given a black image on a foggy blue-grey background.

Example VIII White paper of weight g./m. coated on one side with a cellulose acetate film layer (approximately 50% by weight of combined acetic acid) of a thickness of approximately 10 microns, which layer has been afiixed to the paper by means of an adhesive and de-acetylated to a depth of about 4 microns to an average acetyl content, calculated as combined acetic acid, of 20% by Weight (which corresponds to an average number of acyl groups at the OH-groups of 0.7), is impregnated on the de-acetylated side of the cellulose acetate layer with the following solution:

37.8 g. of 4-allylthio-S-methoxy-Z-N-ethoxycarbonyl-N- methylaminobenzene diazonium chloride, zinc chloride double salt g. of tartaric acid g. of the sodium salt of naphthalene-1,3,6-trisulphonic acid 2.5 g. of gum arabic 100 ml. of ethanol (96%) 900 ml. of water and dried.

A sheet of the dried diazotype material is imagewise exposed as described in Example IV and developed with developer B.

The copy thus obtained shows a brown image on a clear white background.

If, in the above sensitizing liquid, an equivalent quantity of the corresponding 4-allythio-2,5-dimethoxybenzene diazonium compound had been used, the diazotype material thus obtained would have been considerably less lightsensitive, would have had a lower developing speed, and would have given copies with black azo-dyestuff images.

The diazonium compound used according to this example is prepared as follows:

5 methylamino 4-nitro-2-methoxy-l-chlorobenzene, prepared as described in Example II, is brought into reaction with allylmercaptan and then acetylated with the ethyl ester of chloroformic acid. 4-allylthio-2-N- methylamino-S-methoxy-l-nitrobenzene is thus obtained in the form of a dark red oil. From. this nitro compound the diazonium salt is obtained in the usual way.

Example IX A clear cellulose acetate film of 150 g./m. with an acetyl content of about 2.5 is superficially hydrolysed to a depth of about 4 microns and, after removal of the chemicals used for the hydrolysis by washing with water, is sensitized with a solution of:

51 g. of 4-hydroxyethylthio-5-methoxy-2-N-methyl-N- ethoxycarbonylaminobenzene diazonium chloride, zinc chloride double salt 7.5 g. of citric acid 15 g. of the sodium salt of napthalene-1,3,6-trisulphonie acid 250 ml. of ethanol (96%) 750 ml. of water and dried.

The hydrophilic light-sensitive layer obtained after drying contains about 0.5 millimol of diazonium compound per m? of sensitized surface.

A sheet of the light-sensitive diazotype material thus obtained is imagewise exposed as described in Example IV and then developed with developer B.

The copy shows a brown-red image on a crystal-clear background. The azo-dyestuif image has good absorp tion for ultra-violet radiation.

The diazonium compound used according to this example is prepared as follows:

5 methylamino 4-nitro-2-methoxy-l-chlorobenzene is brought into reaction with hydroxyethylmercaptan and then acylated with the ethylester of chloroformic acid. 4 hydroxyethylthio 2 N-ethoxycarbonyl-N-methylamino-S-methoxy-l-nitrobenzene, melting at 174 C., is obtained.

From this nitro compound the diazonium compound is obtained in the usual way.

Example X White base paper of weight 80 g./rn. suitable for the diazotype process is sensitized with a liquid containing:

20 g. of 4 (4' methylphenyl)thio-S-methoxy-Z-N-isobutoxycarbonyl N methylaminobenzene diazonium chloride, zinc chloride double salt 5 g. of tartaric acid 22 g. of non-colloidal silica 1.3 g. of carboxymethylamylose 50 m1. of an anionic polyvinyl acetate dispersion 900 ml. of water and dried.

A sheet of the diazotype paper thus obtained is imagewise exposed as described in Example 1V and then developed with developer A.

The copies thus obtained show an intensive brownblack image on a clear white background.

If, in the above sensitizing solution, an equivalent quantity of the corresponding 4-(4'-methylphenyl)thi0-2,5- dimethoxybenzene diazonium compound had been used, the diazotype paper thus obtained would have been considerably less light-sensitive, would have had a lower developing speed, and would have given copies with a blueblack azo-dyestuff image.

The diazonium compound used in this example is prepared as follows:

5 methoxy 4 (4' methylphenyl)thio 2 methylamino-l-nitrobenzene, prepared as described in Example III, is .acylated with the isobutyl ester of chloroformic acid. The product thus obtained melt-s at 77-79 C.

It is converted into the diazonium salt in the usual way.

Example XI To ml. portions of a stock solution containing:

5 g. of tartaric acid 2 g. of boric acid 2.5 g. of gum arabic 10 ml. of glycerol 40 g. of rice starch 30 ml. of Vinnapas H60 1000 ml. of water is added 0.35 milli-equivalent each of the following diazonium compounds:

(1) 4 ethylthio 5 cyclopentoxy 2 N acetyl N- methylaminobenzene diazonium chloride, zinc chloride double salt.

(2) 4 p tolylthio 5 p chlorophenoxy 2 N acetyl N-methylaminobenzene diazonium chloride, zinc chloride double salt.

(3) 4 carboxymethylthio 5 methoxy 2 N ethoxycarbonyl-N-methylaminobenzene diazonium chloride, zinc chloride double salt.

(4) 4 ethylthio 5 methoxy 2 N phenoxycarbonyl- N-methylaminobenzene diazonium chloride, zinc chloride double salt.

(5) 4 cyanothio 5 methoxy 2 N ethoxycarbonyl- N-methylaminobenzene diazonium chloride, zinc chloride double salt.

(6) 4 ethoxycarbonylthio 5 methoxy 2 N ethoxycarbonyl-N-n-butylaminobenzene diazonium chloride, zinc chloride double salt.

(7) Ethane 1,2 dithiol bis (4' diazo 2' methoxy- 5 N ethoxycarbonyl N methylaminophenyl)ether, chlorozincate.

With each of the seven sensitizing liquids thus prepared, a sheet of white base paper for the diazotype process is sensitized.

The sheets are marked with the figures 1 to 7, so that the figures correspond with those of the diazonium compounds in question.

The seven sheets are exposed underneath a transparent ink drawing until all the diazonium compound underneath the image-free portions of the drawing has bleached out. Then each of the sheets is divided into two equal parts. One half is marked with an a and then developed with developer B; the other half is marked with a b and then developed with developer D.

All the materials are found to be very light-sensitive and to have a very high developing speed.

All the copies show a white background. The azo dyestufr" image of:

sheet la is violet-brown and that of sheet lb is light-brown sheet 2:: is dark-brown and that of sheet 2b is light-brown sheet 3:: is brown-red and that of sheet 3b is yellow-brown sheet 4a is violet-black and that of sheet 4b is brown sheet 5a is red and that of sheet 5b is orange-brown sheet 6a is brown and that of sheet 6b is light-brown sheet 7a is brown-red and that of sheet 7b is yellow-brown.

Diazonium compound No. l is prepared as follows: p-chlorophenol is converted with cyclopentyl bromide into 4-chloro-l-cyclopentoxybenzene. The product thus obtained is nitrated, after which the nitro group thus introduced is reduced and the amino group thus formed is acetylated.

The 5-ch1oro-2-cyclopentoxy-Nacetylaniline is nitrated and then de-acetylated. The chlorine atom is subsequently replaced by a monomethylamino group and the free amino group is replaced by a chlorine atom according to Sandmeyer. The 4 chloro 5 cyclopentoxy 2 methylamino-l-nitrobenzene is brought into reaction with ethylmercaptan and then acylated with acetyl chloride. The 4 ethylthio 5 cyclopentoxy 2 N acetyl N methylamino-l-nitrobenzene melts at 108111 C. This nitro compound is converted into the diazonium salt in the usual way.

Diazonium compound No. 2 is prepared from S-chloro- 2-p-chlorophenoxyaniline, which is supplied by Rohner A.G., Pratteln, Switzerland, under the trade name FR- base. The product in question is acetylated, nitrated, and de-acetylated. The S-chloro-4-nitro-2-p-chlorophenoxyaniline is brought into reaction with monomethylamine, after which the free amino group is replaced by a chlorine atom according to Sandmeyer. This chlorine atom is subsequently replaced by a p-tolylthio group. Into the monomethylamino group an acetyl group is introduced with the aid of acetyl chloride.

The 4-p-tolylthio-5-p-chlorophenoXy-2 N acetyl N- methylamino-l-nitrobenzene melts at 161162 C. From this nitro compound the diazonium salt is obtained in the usual way.

Diazonium compound No. 3 is prepared from S-chloro- 2-methoxyaniline. This product is acylated, nitrated, and deacy1ated, and subsequently brought into reaction with monomethylamine. The 4-nitr-o-S-methylamino-Z-methoxyaniline is converted into 4-chloro-S-methoxy-Z-methylamino-l-nitrobenzene according to Sandmeyer.

The chlorine atom of the latter product is replaced by a carboxymethylthio group with the aid of thioglycolic acid, after which the monomethylamino group is acylated with the ethyl ester of chloroformic acid.

The 4-carboxymethylthio-S-methoxy-Z N ethoxycarbonyl-N-methylarnino-l-nitrobenzene, melting at 172 174 C., is converted into the diazonium salt in the usual way.

Diazonium compound No. 4 is prepared from 4-cl1loro- S-methoxy-Z-methylamino-1-nitrobenzene (see the preceding preparation). This product is brought into reaction with ethylmercaptan and then acylated with the phenyl ester of chloroformic acid. The 4-ethylthio-5- methoxy-2-N-phenoxycarbonyl-N-methylamino-1 nitrobenzene melts at l3l133 C. It is converted into the diazonium salt in the usual way.

Diazonium compound No. 5 is prepared from p-anisidine, which for this purpose is acylated, nitrated, and deacylated. The amino group of the 4-methoxy-2-nitroaniline is replaced according to Sandmeyer by a chlorine atom, which is subsequently replaced by a monomethylamino group. The S-methoxy-Z-methylamino-l-nitrobenzene is acylated with the ethyl ester of chloroformic acid, after which the product of the acylation is brought into reaction with bromine and potassium rhodanide. The nitro group of the 4-cyanothio-S-methoxy-Z-N-ethoxycarbonyl-N-methylamino-l-nitrobenzene is reduced, and the amine thus formed, which melts at 142 C., is diazotized. The diazonium compound is obtained in the form of the chlorozincate.

Diazonium compound No. 6 is prepared :from 5-chloro- 2-methoxyaniline. This product is acylated, nitrated, deacylated, and then brought into reaction with mono-nb-utylamine. The 4-nitro-5-n-butylamino 2 methoxyaniline is converted according to Sandmeye-r into 4-ch1oro 2-n-butylamino-5-methoxy-l-nitrobenzene, which is subsequently converted by means of Na S and sulphur into 4-NaS-2-n-butylamino-S-methoxy-1 nitrobenzene, which melts at 130-132 C. This product is acylated with the ethyl ester of chloroformic acid. The 4-ethoxycarbonylthio-2-N-n-butyl-N-ethoxycarbonylamino-S-rnethoxy 1- nitrobenzene is a red-brown oil. From the nitro compound the diazonium salt is obtained in the usual way.

Diazonium compound No. 7 is prepared from 4-chloro- S-methoxy-Z-rnethylamino-l-nitrolbenzene (see: preparation of diazo compound No. 3). This product is converted with ethane-1,2-dithiol and then acylated with the ethyl ester of chloroformic acid.

Ethane-dithiol-bis(4-nitro-5'-N ethoxycarbonyl N- methylamino-2-methoxyphenyl)ether is obtained, which melts at 175 C. and from which the his (diazonium chlorozincate) is obtained in the usual way.

Example XII White base paper of weight g./n1. suitable for the diazo type process which has been precoated with an aqueous dispersion of silica and then dried, is sensitized with a liquid containing:

8 g. of 4-ethylthio-5-methoxy-2-N-methyl-N-acetylaminobenzene diazonium chloride, zinc chloride double salt 8 g. of tartaric acid 4 g. of boric acid 600 ml. of Vinnapas H60 400 ml. of water and dried.

On the light-sensitive layer an intermediate layer is formed by applying a solution of:

g. of the polyvinyl acetate Vinnapas U.W.50 in 1000 ml. of trichloroethene and drying.

On the intermediate layer a top layer is formed With the aid of a liquid containing:

5 g. of 2,B-dihydroxyna-phthalene 20 g. of non-colloidal silica 46 g. of N-acyl-N'-2-hydroxyethylethylenediamine Nalcamine A12 (from Nalco Chemical Co., Chicago 38, 111., USA.)

1000 ml. of petroleum ether.

The dried light-sensitive material is imagewise exposed underneath a transparent India ink drawing until the diazonium compound underneath the image-free portions of the drawing ha bleached out, and is then developed by guiding it over a heated roller having a temperature of about C., the back of the sheet contacting the roller surface.

The copy shows a red image on a white background.

The diazonium compound used in this example is prepared as follows:

5-methylamino-4-nitro-2-methoxy-l-chlorobenzene (see Example II) is brought into reaction with ethylmercaptan. The reaction product is acetylated. The 5-methoxy-4- ethylthio-2-N-acetyl-N-methylarnino-1 nitrobenzene thus obtained melts at 162164 C. This nitro compound is reduced to the corresponding amino compound, which is then diazotized. The resulting diazonium compound is obtained in the form of the zinc chloride double salt.

1 Example XIII White base paper of weight 80 g/m. suitable for the diazo-type process is sensitized with a liquid containing:

16 g. of 4-ethylthio-S-methoxy-Z-N-rnethyl N ethoxycarbonylaminobenzene diazonium chloride zinc chloride double salt 20 g. of tartaric acid 5 g. of boric acid 20 g. of the sodium salt of naphthalene-1,3,6-trisulphonic acid 2.5 g. of gm. arabic g. of 7'-hydroxy-1',2',4,5-naphthimidazole 30 ml. of Vinnapas H60 1000 ml. of water and dried.

A sheet of the two-component diazotype paper thus obtained is i'magewise exposed as described in Example II and then developed in ammonia vapour.

The copy shows a red image on a foggy red background.

If, in the above sensitizing liquid, an equivalent quantity of the corresponding 2,5-dimethoxy compound had been used, the diazotype paper thus obtained would have been much less light-sensitive and would have had a lower developing speed.

The diazonium compound used in this example can be prepared as follows:

4-ethylthio-2,S-dirnethoxy-l-nitrobenzeme (prepared for instance, as described in Dutch patent specification No. 51,536) is heated for hours with 'monomethylamine in an autoclave at a pressure of about 5 atmospheres. The reaction product is acylated with the ethyl ester of chloroformic acid, after which from the 4-ethyl-thio-5- methoxy-Z-N-methyl-N-ethoxycarbonylamino 1 nitrobenzene thus formed, the diazoniurn compound is obtained in the usual way.

What we claim is:

1. A light-sensitive diazoniu-m compound of the general formula wherein:

X is an anion; R is alkyl, cycloalkyl or aralkyl; R is hydrogen or an organic radical; R is an acyl, aliphatic, cycloaliphatic, aralkyl, aryl or cyano group; and R is alkyl, cycloalkyl, aralkyl or aryl.

2. A light-sensitive diazonium compound of the general formula NQX wherein:

X is an anion;

R is alkyl, cycloalkyl or aralkyl;

R is hydrogen or an organic radical;

SR is an etherified mercapto, acylmercapto or cyanomercapto group; and

R is alkyl, cycloalkyl, aralkyl or aryl.

3. A diazonium compound according to claim 2 wherein R is a non-branched alkyl group of 1 to 5 carbon atoms.

4. A diazonium compound according to claim 2 wherein R is alkoxy, benzyloxy or phenoxy.

5. A diazonium compound according to claim 2 wherein R is alkyl, cycloalkyl, aralkyl or aryl.

6. A diazonium compound according to claim 2 wherein R is methyl.

7. A diazonium compound according to claim 2, wherein R is a non-branched alkyl group of 1 to 5 carbon atoms; R is alkoxy, benzyloxy or phenoxy;

R is alkyl, cycloalkyl, aralkyl or aryl; and

R is methyl.

8. A diazonium compound according to claim 2 in the form of a bis-amide comprising two structures of the said formula joined together through inter-linked carbonyl radicals attached to the respective nitrogen atoms iocated ortho to the respective diazonium groups.

9. A diazonium compound according to claim 8, said carbonyl radicals being inter-linked by an ethylene group.

10. A diazonium compound according to claim 2 in the form of a dithiol-bis-ether comprising two structures of the said formula joined together through inter-linked CH groups attached to the respective sulfur atoms located para to the respective diazoniurn groups.

11. A diazotype material comprising a support carrymg a light-sensitive layer containing a light-sensitive diazoniurn compound as defined in claim 2.

12. A one-component diazotype material comprising a support carrying a light-sensitive layer containing a diazonium compound as defined in claim 4, in the substantial absence of an azo coupling component.

13. A one-component diaz-otype material comprising a support carrying a light-sensitive layer containing a diazonium compound as defined in claim 7, in the substantial absence of an azo coupling component.

14. A two-component diazotype material comprising a support carrying a light-sensitive layer containing a diazonium compound as defined in claim 2 and an azo coupling component.

15. A diazotype process which comprises subjecting an i'magewise exposed diazotype material as defined in claim 11 to treatment with a developer comprising resorcinol or phloroglucinol.

References Cited by the Examiner UNITED STATES PATENTS 6/1942 Werner -1 96-91 1/1962 Sanders et al. 96-91 

1. A LIGHT-SENSITIVE DIAZONIUM COMPOUND OF THE GENERAL FORMULA 1-(X-N=N-),2-(R2-CO-N(-R1)-),4-(R3-S-),5-(R4-O-)-BENZENE
 11. A DIAZOTYPE MATERIAL COMPRISING A SUPPORT CARRYING A LIGHT-SENSITIVE LAYER CONTAINING A LIGHT-SENSITIVE DIAZONIUM COMPOUND AS DEFINED IN CLAIM
 2. 